I think your idea of dividing everything by 10 is a great idea. Just choose the largest paper size (Arch B) and drawing are (1800x1200 Feet) and size eveything 10 times smaller, so 3000 feet become 300 ft etc. It's easy to add the extra '0' in your head to make the conversion. Note that if you use any of the pre-made symbols from the sybmols library, you will have to scale them down by a factor of 10 as well. The easiest way to do that is to select the symbol, then right-click and select Scale > Enter Custom Scale and enter 10%.
Alternatively, you could change your units to 'metric' and use 3000 mm instead of feet, which will defintely fit on the page.